Ah alam ko yan, sobrang exciting talaga bumili ng home doppler! From what I've read and what a few of my mum friends shared, around 12 weeks pa lang makikita mo na heartbeat pero mas clear at consistent siya around 16-20 weeks onwards, kaya if you're earlier than that, huwag magalala kung mahirap pa marinig. Pero honestly, better to double-check with your OB kung gaano ka-weeks ka na ngayon at kung safe for your situation ang regular use ng doppler, kasi iba-iba talaga ang pregnancy journey ng bawat mommy!